Abrasive composition



' Patented Mar. 6, 1928.

UNITED STATES PATENT OFFICE.

HENRY R. POWER, OF NIAGARA FALLS, NEW YORK, ASSIGNOR TO THE GARBORUNDUM COMPANY, OF NIAGARA. FALLS, NEW YORK, A CORPORATION OF PENNSYLVANIA.

ABRASIVE COMPOSITION.

No Drawing.

My invention relates to abrasive compositions for grinding metal surfaces, such as valve seats for internal combustion engines, although the composition may be used for any grinding operation where a tight joint is desired between the two metal surfaces.

The present grinding compositions for such purposes are of two classes, one class comprising the abrasive grains mixed with ease or oil. On account of the lubricatmg action of the grease or oil, the full cutting value of the abrasive grains is not obtained in this class. In the second class, the abrasive grains are mixed with water and an organic binder such as gum, starch, lichen or seaweed. The objection to this class is that on dryin a skin of the dried organic binder is ormed and when this is again wet it forms clots. These clots are ob'ectionable since they are likely to drop oil from the valve seat and fallon the engine and cause damage in subsequent operation.

I have discovered a composition which overcomes all these objections and makes a bond free from organic material. This inorganic bond is preferably a finely divided mineral which is mixed with the abrasive grains and will form a smoth paste with water.

I preferably employ for this purpose fullers earth and especially that variety of this mineral known as bentonite. -Bentonite,

when mixed with water, adsorbs the water to 9. ve large amount to form a gelatinous mass. ommercially, it is called mineral m, and it is this type of material which preferably employ as the jelly-forming substance to carry the abrasive grains of my abrasive composition.

In the preferred form of carrying out my invention, I first 'mix the mineral gum with about 6 arts of water to form a smoth paste, an then add the desired amount of abrasive grains, which amount depends upon the purpose to which the grinding composition is to be put and also on the size of the abrasiveparticles. I also preferably add glycerine to give smoother consistency and Application filed May 31, 1922. Serial No. 564,959.

to retard evaporation. One formula I have employed with success is as follows 7 However, I do not desire to limit myself to this formula nor to the use of glycerine nor to the use of silicon carbide as the abrasive.

The advantages of this invention will be obvious to those skilled in the art, since there is no lubricant to interfere with the cutting actions of the particles and the material dries without a skin and forms no clots and may be readily made up again into a paste. frozen without destroying its jell -forming properties, whereas organic jel ies when frozen lose their jelly characteristics when again thawed out. These organic jellies, therefore, require an electrolyte, such as calcium chloride, to prevent freezing. This adds to the cost of the mixture and also causes corrosion of the container before the Furthermore, my paste may bepaste is put into use. Such electrolytes are i also likely to cause corrosion of'the valve seats if not thoroughly wiped off after the grinding operation. A further advantage of my composition is that it may be mixed with cold water since no heat is required at any stage of the manufacture; whereas in the former types, heat was required to form a smooth paste.

Changes may be made in the abrasive and the inorganic material used, the formula employed, the proportions used, etc., without departing from my invention.

I claim:

1. A paste for metal inding formed with an inorganic material? having a high absorptive power and having a granulated abrasive material incorporated therein said paste also containing glycerine and being free of silicate of soda.

2. As a new composition of matter, a grinding composition containing 8 parts of bentonite, 40 parts of silicon carbide, 49 absorptive power and having granulated parts of water, and 3 lparts of glycerine. abrasive material incorporated therein, said 3. A paste for meta grinding comprising paste also containing water and a material bentonite and water and having a granufor retarding the evaporation of the water,

5 lated abrasive material mixed therein and a the paste being free of silicate of soda.

substance in the paste for lowering the In testimony whereof I have hereunto set freezing point of the water. my hand.

4. A paste for metal inding formed with an inorganic materizfi having a high HENRY R. POWER. 

